Modification of Surfaces by Chemical Transfer Printing Using Chemically Patterned Stamps

The preparation of well-defined molecular monolayers and their patterning on the microscale and nanoscale are key aspects of surface science and chemical nanotechnology. In this article, we describe the modification of amine-functionalized surfaces using a new type of contact printing based on chemically patterned, flat PDMS stamps. The stamps have discrete areas with surface-bond tetrafluorophenol (TFP) groups, which allow the attachment of carboxylic acids in the presence of coupling agents such as diisopropylcarbodiimide (DIC). The generated active esters can be reacted by placing the stamps in contact with amine-functionalized surfaces. The process leads to the transfer of acyl residues from the stamp to the substrate and therefore to a covalent attachment. Patterning occurs because of the fact that reaction and transfer take place only in areas with TFP groups present on the stamp surface. Different types of amine-decorated surfaces were successfully modified, and the transfer was visualized by fluorescence microscopy. To the best of our knowledge, the covalent transfer printing (CTP) of an immobilized molecular monolayer from one surface to another surface is unprecedented

Navigating Hybridity and Female Empowerment in Anca’s Journey: A Feminist and Cultural Analysis of Migration and Identity

This research examines Ruth Siburt’s ‘Anca’s Journey’ through the lenses of Liberal Feminism and Cultural Hybridity, focusing on how the story addresses traditional gender roles and the complexities of migration. Using Betty Friedan’s Liberal Feminism (1963) to explore themes of female empowerment through education and Homi K. Bhabha’s Cultural Hybridity (1994) to analyze identity negotiation as a secondary theory, As the results: 1) Anca’s Journey subverts traditional gender roles by portraying Anca’s intellectual growth as a central form of empowerment. Her education allows her to transcend societal expectations typically placed on young girls, aligning with Friedan’s feminist ideals. 2) The story highlights the resilience and agency of its female characters, particularly Anca and her mother, as they navigate societal pressures in a patriarchal, migration-focused narrative. Anca’s refusal to accept labels like "lame" demonstrates her resistance to restrictive social judgments, while her mother’s protective role illustrates maternal agency. 3) Anca's intellectual growth is a key factor in her ability to navigate her cultural environment, as she balances the expectations of her Romanian heritage with her new life in America. This reflects both feminist and hybrid identity formation theories. These findings illustrate how Anca’s Journey not only challenges traditional gender expectations but also reflects the broader social realities of migration, using education as a means of empowerment and identity negotiation

Navigating Hybridity and Female Empowerment in Anca’s Journey: A Feminist and Cultural Analysis of Migration and Identity

This research examines Ruth Siburt’s ‘Anca’s Journey’ through the lenses of Liberal Feminism and Cultural Hybridity, focusing on how the story addresses traditional gender roles and the complexities of migration. Using Betty Friedan’s Liberal Feminism (1963) to explore themes of female empowerment through education and Homi K. Bhabha’s Cultural Hybridity (1994) to analyze identity negotiation as a secondary theory, As the results: 1) Anca’s Journey subverts traditional gender roles by portraying Anca’s intellectual growth as a central form of empowerment. Her education allows her to transcend societal expectations typically placed on young girls, aligning with Friedan’s feminist ideals. 2) The story highlights the resilience and agency of its female characters, particularly Anca and her mother, as they navigate societal pressures in a patriarchal, migration-focused narrative. Anca’s refusal to accept labels like "lame" demonstrates her resistance to restrictive social judgments, while her mother’s protective role illustrates maternal agency. 3) Anca's intellectual growth is a key factor in her ability to navigate her cultural environment, as she balances the expectations of her Romanian heritage with her new life in America. This reflects both feminist and hybrid identity formation theories. These findings illustrate how Anca’s Journey not only challenges traditional gender expectations but also reflects the broader social realities of migration, using education as a means of empowerment and identity negotiation

Photochemical Microcontact Printing by Tetrazole Chemistry

We developed a simple method to pattern self-assembled monolayers of tetrazole triethoxylsilane with a variety of different molecules by photochemical microcontact printing. Under irradiation, tetrazoles form highly reactive nitrile imines, which react with alkenes, alkynes, and thiols. The covalent linkage to the surface could be unambiguously demonstrated by fluorescence microscopy, because the reaction product is fluorescent in contrast to tetrazole. The modified surfaces were further analyzed by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), atomic force microscopy (AFM), and contact angle goniometry. Protein-repellent micropatterns, a biotin–streptavidin array, and structured polymer brushes could be fabricated with this straightforward method for surface functionalization

Polymer Brushes Exhibiting Versatile Supramolecular Interactions Grown by Nitroxide-Mediated Polymerization and Structured via Microcontact Chemistry

Functionalization of metal, glass, and semiconductor substrates with polymers and nanoparticles is a key challenge for surface-based material science. Such substrates have the potential to find widespread application in optical and electronic devices, microarrays, and materials for information storage. We report site-specific immobilization of nitroxide-mediated polymerization initiators via microcontact chemistry employing thiol–ene click chemistry on glass-supported alkene-terminated self-assembled monolayers. The polymer initiator covered substrates are used for preparation of poly­(styrene) and poly­(acrylate) brushes with defined and tunable brush thicknesses. Brush thickness dependent site-specific protein adsorption of streptavidin and concanavalin A on structured polystyrene brushes is reported. Poly­(styrene) brushes with a thickness of 40 nm or larger showed protein repellence whereas brushes below 15 nm thickness reveal protein adhesive properties. We also disclose the site selective host–guest assisted immobilization of β-cyclodextrin-coated silica nanoparticles and the tethering of liposomes modified with amphiphilic β-cyclodextrin onto adamantane-functionalized poly­(acrylate) brushes. Selective immobilization of these supramolecular colloids via the multivalent hydrophobic inclusion complex of β-cyclodextrin and adamantane can be readily verified by fluorescence microscopy imaging, atomic force microscopy, and quartz crystal microbalance with dissipation monitoring

A microfluidic device with continuous ligand gradients in supported lipid bilayers to probe effects of ligand surface density and solution shear stress on pathogen adhesion

Studying binding interactions involving living cells requires a platform that carefully mimics the physiological parameters that govern these phenomena. Very often the amount of ligands that receptors can bind affect overall binding strength as is the case in cell adhesion. In addition, the physical environment can strongly influence these processes. This is exemplified by the effect of shear stress in catch-bond-mediated binding of bacteria. Traditional analysis techniques do not allow to probe these factors simultaneously. To this end, continuous ligand gradients in locked-in supported lipid bilayers (SLBs) are prepared in a microfluidic device to control fluid flow. This platform allows for one-pot characterization of cell surface binding events and 1) the effect of ligand density and 2) shear stress, simultaneously. The model interaction between the FimH receptor found on Escherichia coli and mannose found on the mammalian cell membrane is used to evaluate the platform. Using a single chip, specific E. coli ORN 178 adhesion (K d of 0.9 × 10−21 m), detachment and displacement are shown to depend on the mannose-density and shear stress. For the first time, these effects are studied in a single chip device with high quality. This chip provides entry to further our understanding of other cell–cell interaction

K₂Hg₂Se₃: Large-Scale Synthesis of a Photoconductor Material Prototype with a Columnar Polyanionic Substructure

K₂Hg₂Se₃, a new photoconducting material with a direct band gap around 1.4 eV, was obtained in nearly quantitative yields and large scale (50 g per batch) by means of solvothermal treatment of a corresponding solid. The compound comprises covalently linked selenidomercurate columns that accommodate potassium counterions. Composition and structure allow for a specific combination of optoelectronic, photophysical, and thermoelectric properties, which initiates a systematic material development within this family of compounds